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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
We went ahead and swapped out the CPS with a known good part, and no joy. I checked for power at the coil plug. There is no power at the coil plug when the key is on. Also there is no power at the fuel injectors. I can feel all the relays in the PDC energizing with cycling of the key. I swapped around all the relays. By the way could someone tell me which relay is the ASD relay? All the fuses on the PDC check good for power.
Without knowing exactly which relay to start jumping, we will be swapping out the ignition switch. We pulled off the ignition switch plug and one of the pins looks overheated. I did purchase the FSM, but as we know this year Jeep does not match...
All the fuses in the PDC check good for voltage. Relays in the PDC have been swapped around and I can hear the coils energize. With the key turned to RUN I get 12V at the ignition coil plug and fuel injector plugs for two seconds. The ignition coil and crankshaft position sensor have been swapped with known good parts. I have good power in and out of the ignition switch verified with a headlight. I still have no spark. All the fuses on the junction box check good for voltage but one. It is a 5A fuse located at the top of the junction box, labeled 19. I do not have 12V on either side of the fuse. I do not have the correct FSM drawings. I purchased the 1996 XJ FSM and does not match this Jeep. If someone could help me out with which FSM to buy I would appreciate it. This Jeep seems to be the typical mix of pre-'96 and post-'96 parts, very frustrating.
All the fuses on the junction box check good for voltage but one. It is a 5A fuse located at the top of the junction box, labeled 19.
You must be referring to the fuse panel underneath the dash on the driver's side. If so, it should be at the bottom of the fuse box, unless the diagram I am looking at is wrong, but I doubt it because it is the original owners manual. Anyway, 19 is Instrument Pane Lamps, Radio Illumination.
Last night I swapped the '96 ECU with a '98 ECU, still no spark but the CEL was gone. Pulled the dipstick ground stud, and the grounds under the ECU apart again to see if any ground wires shook loose. All is well there. We figured out that our mystery fuse is powered by the headlight switch. Did the NSS test and found that the engine did not crank in neutral. Used my Fluke and found that it does have issues, so we will be swapping it out sometime today. I understand that NSS serves multiple functions with the transmission and starting, but can it cause a no spark condition? On another note, I went ahead and purchased the 1998 XJ FSM not only because I have a 1998 XJ but because I was hoping the wiring diagrams would match this 1996 XJ...it does not.
You must be referring to the fuse panel underneath the dash on the driver's side. If so, it should be at the bottom of the fuse box, unless the diagram I am looking at is wrong, but I doubt it because it is the original owners manual. Anyway, 19 is Instrument Pane Lamps, Radio Illumination.
Thanks OldTires. The panel in my Jeep is mounted 180 degrees out. I traced back all the 5A fuses and realized that the fuse in question got its power from the headlight switch. I will need to keep looking for that relay panel for future reference.
My son could not easily get the NSS out of my '91XJ, so we cracked his open nd cleaned it up. It now ohms out correctly now, but after install; still no spark. Since the only thing that I have not checked is the camshaft position sensor, I found some old posts on how to use a multimeter to look at the 5V reference signal and the 5V that the sensor sends to the ECU. Guess what BlueRidgeMark, I have no 5V signal out of the camshaft position sensor. I checked my '98XJ the same way and I get a good voltage pulse as it is cranking. I only have a Fluke at the moment, so I could not get a good look at the 5V output. When the boss releases some funds for a new distributor, I will be off to the parts store.
The new distributor will fix my Jeep. However, we still have much work to do. I will now describe the chain of events. My son added a 3 inch lift, which lead to a VIOLENT death wobble. The death wobble sheared the bolts off of the motor mount and the distributor was holding up the weight of the engine. The distributor fractured causing the sensor to be misaligned and not working. Fun stuff... Please see the photo below for your enjoyment.
I guess the biggest lesson when your Jeep doesn't start, is to first look around in the engine bay, look under the engine, poke around, before anything else. Then look for broken wires, contacts, vacuum tubes, etc.. Being methodical and obsessive pays off.
07-20-2018, 10:27 PM
